Leviticus 5:15

5:15 “When a person commits a trespass and sins by straying unintentionally from the regulations about the Lord’s holy things, then he must bring his penalty for guilt to the Lord, a flawless ram from the flock, convertible into silver shekels according to the standard of the sanctuary shekel, for a guilt offering.

Leviticus 5:18

5:18 and must bring a flawless ram from the flock, convertible into silver shekels, for a guilt offering to the priest. So the priest will make atonement on his behalf for his error which he committed (although he himself had not known it) and he will be forgiven.